<template>
  <div class="s-canvas">
    <canvas id="s-canvas" :width="contentWidth" :height="contentHeight"></canvas>
  </div>
</template>
<script setup lang="ts">
const props = defineProps({
  identifyCode: {
    type: String,
    default: "1234",
  },
  fontSizeMin: {
    type: Number,
    default: 30,
  },
  fontSizeMax: {
    type: Number,
    default: 40,
  },
  backgroundColorMin: {
    type: Number,
    default: 180,
  },
  backgroundColorMax: {
    type: Number,
    default: 240,
  },
  colorMin: {
    type: Number,
    default: 50,
  },
  colorMax: {
    type: Number,
    default: 160,
  },
  lineColorMin: {
    type: Number,
    default: 40,
  },
  lineColorMax: {
    type: Number,
    default: 180,
  },
  dotColorMin: {
    type: Number,
    default: 0,
  },
  dotColorMax: {
    type: Number,
    default: 255,
  },
  contentWidth: {
    type: Number,
    default: 112,
  },
  contentHeight: {
    type: Number,
    default: 48,
  },
})
const randomNum = (min: number, max: number) => Math.floor(Math.random() * (max - min) + min)
const randomColor = (min: number, max: number) => {
  let r = randomNum(min, max)
  let g = randomNum(min, max)
  let b = randomNum(min, max)
  return "rgb(" + r + "," + g + "," + b + ")"
}
const drawText = (ctx: CanvasRenderingContext2D, txt: string, i: number) => {
  ctx.fillStyle = randomColor(props.colorMin, props.colorMax)
  ctx.font = randomNum(props.fontSizeMin, props.fontSizeMax) + "px SimHei"
  let x = (i + 1) * (props.contentWidth / (props.identifyCode.length + 3))
  let y = randomNum(props.fontSizeMax, props.contentHeight + 1)
  var deg = randomNum(-5, 5)
  // 修改坐标原点和旋转角度
  ctx.translate(x, y)
  ctx.rotate((deg * Math.PI) / 180)
  ctx.fillText(txt, 0, 0)
  // 恢复坐标原点和旋转角度
  ctx.rotate((-deg * Math.PI) / 180)
  ctx.translate(-x, -y)
}
const drawLine = (ctx: CanvasRenderingContext2D) => {
  // 绘制干扰线
  for (let i = 0; i < 6; i++) {
    ctx.strokeStyle = randomColor(props.lineColorMin, props.lineColorMax)
    ctx.beginPath()
    ctx.moveTo(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight))
    ctx.lineTo(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight))
    ctx.stroke()
  }
}
const drawDot = (ctx: CanvasRenderingContext2D) => {
  // 绘制干扰点
  for (let i = 0; i < 100; i++) {
    ctx.fillStyle = randomColor(0, 255)
    ctx.beginPath()
    ctx.arc(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight), 1, 0, 2 * Math.PI)
    ctx.fill()
  }
}
const drawPic = () => {
  let canvas = document.getElementById("s-canvas") as HTMLCanvasElement
  let ctx = canvas.getContext("2d") as CanvasRenderingContext2D
  ctx.textBaseline = "bottom"
  // 绘制背景
  ctx.fillStyle = randomColor(props.backgroundColorMin, props.backgroundColorMax)
  ctx.fillRect(0, 0, props.contentWidth, props.contentHeight)
  // 绘制文字
  let arrcode = props.identifyCode.split(" ") as any
  for (let i = 0; i < arrcode.length; i++) {
    drawText(ctx, arrcode[i], i)
  }
  drawLine(ctx)
  drawDot(ctx)
}
watch(
  () => props.identifyCode,
  () => {
    drawPic()
  },
  {
    // immediate: true,
    deep: true,
  }
)
onMounted(() => {
  drawPic()
})
</script>
<style lang="scss" scoped>
.s-canvas {
  display: flex;
  align-items: center;
  cursor: pointer;
  #s-canvas {
    border-radius: 10px;
  }
}
</style>
